Ball couplers are known that comprise a male tubular endpiece presenting an outer annular flange with a groove defined behind the flange, and a female tubular endpiece for receiving the male tubular endpiece, the endpieces being designed to be associated with respective elements of the circuit. The male endpiece is held in the female endpiece by locking means that act on balls that are received in the groove behind the annular flange. In general, the locking means comprise a ball-retaining cage mounted via one end on the female endpiece so as to extend beyond the female endpiece, and a grip mounted on the retaining cage so as to be capable of being turned between first and second positions. The grip has internal camming surfaces that are angularly offset relative to one anther and that are arranged so that when the grip is in its first position, the balls are held projecting into the inside of the retaining cage so as to retain the annular flange of the male endpiece, and when the grip is in its second position, the balls are released radially and can be taken to a retracted position, thereby releasing the flange and enabling the male endpiece to be extracted from the female endpiece.
Thus, the coupling is unlocked by causing the grip to turn relative to the sleeve. The risk of such a movement being of accidental origin is limited and this constitutes one of the main advantages of a coupler of this type, since the probability of the coupler being unlocked in untimely manner is small.
The above-mentioned document describes two main embodiments. One of them is an embodiment without a valve member for closing the duct, with the connection being undone while still connected to a source of fluid under pressure. The other includes a valve member, which thus opens when the connection is made and closes when the connection is undone. In that second embodiment, there is a variant in which disconnection takes place in two stages: a first stage during which the valve member is closed and the hose downstream from the connection (downstream relative to the source of fluid under pressure) is purged, and a second stage during which the physical separation of the connection is completed, but without there being any pressure in the connection.
In those embodiments, means are described for returning the grip into a position in which it locks the connection, i.e. a position in which the flange cannot be extracted because it is not possible for the blocking balls to be pushed back radially by the flange during such a movement. This is also the position in which the blocking means are to be found when there is no male endpiece, which position does not act in all of the embodiments described to prevent a connection being made.
The invention relates specifically to a ball coupler in any of the above-mentioned variants in which the grip-return means are improved so as to be even more robust and less expensive to fabricate for a more sophisticated coupler.